1. Technical Field
The present invention relates to a method of manufacturing a printed circuit board.
2. Description of the Related Art
Generally, printed circuit boards (PCBs) are manufactured by patterning one or both sides of a substrate, composed of various thermosetting resins, using copper foil, and disposing and fixing ICs or electronic parts on the substrate to form an electric circuit.
Recently, with the advancement of the electronics industry, electronic parts are increasingly required to be highly functionalized, light, thin, short and small. Printed circuit boards loaded with such electronic parts are also required to be highly densified and thin.
In order to meet the above requirement, a circuit transfer process is being proposed. FIGS. 1 to 7 are sectional views showing a conventional method of manufacturing a printed circuit board using the circuit transfer process. Hereinafter, the conventional method of manufacturing a printed circuit board will be described with reference to FIGS. 1 to 7.
First, as shown in FIG. 1, a first copper foil layer 14a is adhered on one side of a tape 12, and then a first metal barrier layer 16a is formed on the first copper foil layer 14a. Further, a second copper foil layer 14b is adhered on the other side of the tape 12, and then a second metal barrier layer 16b is formed on the second copper foil layer 14b to prepare a carrier 10.
Subsequently, as shown in FIG. 2, a first pattern 18a is formed on the first metal barrier layer 16a, and a second pattern 18b is formed on the second metal barrier layer 16b. Hereinafter, for the convenience of explanation, the assembly of the first copper foil layer 14a, the first metal barrier layer 16a and the first pattern 18a is designated as a first carrier part, and the assembly of the second copper foil layer 14b, second metal barrier layer 16b and second pattern 18b is designated as a second carrier part.
Subsequently, as shown in FIG. 3, the first carrier part and the second carrier part are separated from the tape 12.
Subsequently, as shown in FIG. 4, the first and second carrier parts are placed on both sides of an insulation layer 20 and then pressed to embed the first pattern 18a and the second pattern 18b into the insulation layer 20.
Subsequently, as shown in FIG. 5, the first copper foil layer 14a and the second copper foil layer 14b are removed, and then a via hole 22 for interlayer connection is formed in the insulation layer 20.
Subsequently, as shown in FIG. 6, the via hole 22 is plated to form a plating layer, and then the plating layer formed on the insulation layer 20 and the first and second barrier layers 16a and 16b are removed.
Finally, as shown in FIG. 7, first and second solder resist layers 26a and 26b are formed on both sides of the insulation layer 20, and then first and second openings 28a and 28b for exposing pad regions formed in the first and second solder resist layers 26a and 26b to manufacture a two-layered printed circuit board.
However, when a thin printed circuit board is manufactured using the above conventional method, there is a problem in that the thin printed circuit board is damaged (broken or rolled) and thus processes are delayed. For example, a two-layered thin printed circuit board having a thickness of about 80 μm or less is damaged during a process of forming a via hole 22 (refer to FIG. 5) or a process of forming solder resist layers 26a and 26b. As the thickness of a printed circuit board is decreased, it is difficult to entirely apply the above conventional method.